There is a major need to construct safe molecular adjuvants in new mucosal vaccine development, including those designed to protect from Category A. pathogens and exotoxins. Previous work on this grant focused on defining murine nasal-associated lymphoreticular tissues (NALT) as inductive sites by use of novel nontoxic derivatives of the classical mucosal adjuvant cholera toxin (CT). In addition, we have assessed regulatory cytokines and chemokines in these studies to characterize NALT-based mucosal immunity. These studies have also included characterization of human NALT, e.g., the tonsils and adenoids for both HIV infection as well as for optimal development of mucosal and systemic immunity to prevent sexual transmission of HIV. A total of five original Specific Aims were successfully addressed. The events of September 11, 2001 and the aftermath involving anthrax-tainted letters has led to important new initiatives to assess mucosal immunity to Bacillus anthracis and its three part exotoxin. For this reason, we have chosen to study murine NALT-based mucosal immunity to anthrax using the ADP-ribosylation deficient, molecular mutants of CT and chimeras consisting of A subunit of CT and B subunits of Escherichia coil labile toxin (LT). In this renewal grant, we have proposed five Specific Aims, which when completed, will provide essential new information regarding induction of and the functions for mucosal secretory IgA (S-IgA) and serum IgG subclass and IgA antibodies (Abs) in protection from anthrax, both in vitro and in vivo. The first Specific Aim will compare nontoxic mCTs with native CT given with protective antigen (PA) for induction of protective S-IgA Abs. The second Specific Aim will characterize a new panel of monoclonal anti-PA Abs (mAbs) which include all four IgG subclasses, IgE and IgA. The third Specific Aim will employ a newly developed Brevibacillus expression system to produce mCTs and mCT-A / LT-B chimera adjuvants and PA fusion protein as a potential nasal vaccine to protect from inhalational anthrax. The fourth Specific Aim will establish in vitro respiratory epithelial cells with sensitivity to the exotoxin of anthrax for in vitro studies of S-IgA anti-PA mAbs for neutralization of anthrax exotoxin. The last Specific Aim will establish an in vivo model of nasal administration of anthrax components for development of a method to assess nasal anthrax toxicity and mucosal immunity. [unreadable] [unreadable]